Ivan Cleary has admitted he felt sick in the stomach before Wednesday night's Holden State of Origin opener worrying about how his son was feeling leading into the biggest moment of his short career.

The Wests Tigers coach was in the stands to watch son Nathan Cleary, one of 11 new faces in the NSW side.

While Nathan conceded he struggled to contain his nerves leading into the opening game of the series, his father was equally on edge.

"I just knew how nervous he was going to be," Ivan said.

"I felt kind of sick because I know he gets nervous. I caught up with him before the game and he seemed not too bad. As good as you can be I guess.

"The way he started the game was good. In the end you just want to make sure you don't let anyone down and do the job for your team, which he did. It's hard to explain. I really enjoyed it but I rode every moment."

While NSW had no shortage of highlight reel plays, the Queenslanders had very few things to celebrate.

Some of the brutal defence of Greg Inglis had the Maroons faithful out of their seats, including a bone-rattling shot on Nathan in the second half.

His father said the way he responded to the tackle showed why he is made for the Origin arena.

"I thought that was a really good moment," Ivan said. "He got hit hard legitimately and he held the ball, didn't carry on and got up and played the ball quick and Damien Cook took off out of dummy half. He's thinking properly. That's Origin."

In the lead-up to the game Ivan said his son played like a Queenslander because of his ability to play under pressure and with composure when the team needs it most.

Nathan was never the most naturally gifted footballer, but what he lacks in magic he makes up for in toughness and a determination to make every play count.

"That's always been his strength," Ivan said.

"He's always played like that. He'll improve out of that game. Every level he's gone up in his young life, after the first game he takes it all in and works it out a bit better.

"The next game he comes back a little bit more. I think you have to. For a first-up effort he did his job for the team and didn't look out of place ... to see him in there so stoked and relieved, it's an awesome feeling."

Really like how close these two are. Whether it turns him Nathan playing for the club or not it is great to see a family who really look up to each other. There is so much respect in their relationship.